1. Field of the Invention
The subject invention relates to a heat recovery system for use is an oven to recycle waste treatment air used to treat a product in process in a downstream oven zone and create a preheating air to preheat the product in process in a preheating zone prior to entering the downstream oven zone.
2. Description of the Prior Art
U.S. Pat. No. 4,569,658 to Wiggins et al. discloses an oven system having a baking chamber broken into a plurality of zones. Each zone includes an inlet duct 11 leading into the zone and an outlet duct 8 leading out from the zone. The outlet duct is used to extract exhaust gases from the associated zone and transfer them to an exhaust flue 18. The waste heat present in the exhaust gases are used to raise the temperature of the inflowing ambient air introduced to the inlet duct 11. A heat exchanger 14 is present to transfer heat from the exhaust gases to the inflowing ambient air. The rate at which the ambient air is supplied and exhaust gases are extracted may be varied to compensate for varying rates of steam along the oven.
U.S. Pat. No. 4,109,394 to Hoyt discloses an air flow system for the treatment of particulate materials along a conveyor. The system provides for the flow of fluidizing air to the particulate treatment zone via an array of nozzles 40 arranged to project gaseous streams downwardly against the conveyor and a plurality of ducts 80 arranged to project gaseous streams inwardly along the conveyor. The system includes a housing having a conditioning plenum 48 and a main pressure plenum 46. A plurality of exhaust ports 62 are included to exhaust gases from the system and transport the gases to a cyclone 70. The gases from the cyclone 70 are returned to the housing through duct 72 for flow into the conditioning plenum 48. In the conditioning plenum, the returned gases are heated or cooled as desired and then fed to the main pressure plenum 46 via a blower 50. The main pressure plenum 46 feeds the gases to the nozzles 40 and ducts 80 to treat the particulates along the conveyor. The system recycles the gases within a zone.
U.S. Pat. No. 5,142,794 to Meiners discloses a system for the pretreatment of corn or other grains using the exhaust air from conventional dryer 10. Hot moist air is exhausted from the conventional dryer and transported via a conduit 26 to a steeping container 12 where the corn is pre-treated. The system includes a monitor device 28 to monitor the humidity and temperature of the hot moist exhaust air in the conduit 26. The monitor device 28 is in communication with a heater 30 which is selectively activated to control the humidity and temperature of the exhaust air as it is transported to the steeping container 12. The dryer 10 includes a second exhaust through which cool exhaust air from the dryer 10 is introduced into the conduit 26. The conduit 26 feeds the conditioned exhaust air from the dryer 10 to the steeping container 12 in order to pre-treat the corn or grain in the steeping container 12. The result is a grain with uniform moisture levels being fed from the steeping container 12 to the dryer 10.